Not everyone will observe the same holidays, and not every business or even member of your team will be around at the same time or even days. It is also completely possible that your business will stay open, but adjust operating hours. Either way, recording a personalized holiday greeting for your business can go a long way in improving your customer’s experience.
The greeting that you leave on your phone in the form of a voice mail can be very important as it is the first contact that anyone calling has with you or the company that you work for. Therefore it is important that your voicemail greeting is drafted in such a manner that it does not make the caller squirm in embarrassment, or even raise their eyebrows in sheer wonder. Proper voicemail etiquette demands that a good voicemail message convey information like whom the caller is calling, where they are, when the caller can expect to be called back, and what to do if the call that is being made is of an urgent nature.

I know you're angry because I never answer your phone.So, to fix this, I think you guys should give me a birthday present: cell phone..(Make a little noise in the background ).Hi, you are already at your friend's house.
A monotone voice can be a turn off for a caller. You want your caller to feel like they missed out on speaking with you — not like they dodged a bullet.